Electroacupuncture attenuates inflammation in a rat model

Background: Acupuncture has traditionally been used in China and is being increasingly applied in Western countries to treat a variety of conditions, including inflammatory disease. However, clinical trials investigating the effectiveness of the anti-inflammatory effects of acupuncture have yielded inconsistent results, and the underlying mechanisms of acupuncture-produced anti-inflammation are unclear. Objective: To evaluate the effectiveness of electroacupuncture (EA) on inflammation in a rat model. Materials and methods: Four experiments were conducted on male Sprague-Dawley rats (n = 8-9 per Group). Inflammation was induced by injecting complete Freund's adjuvant (CFA) subcutaneously into the plantar surface of one hind paw of the rat. Experiment 1: To determine the effect of EA (10 and 100 Hz) versus sham treatment on inflammation. Experiment 2: To investigate the involvement of the adrenal glands on the effect of EA treatment using adrenalectomized (ADX) rats. Experiment 3: To determine the effects of EA on plasma levels of corticosterone. Experiment 4: To determine the effects of EA treatment versus immobilization on such stress indicators as heart rate and blood pressure. Results: At 10 Hz EA significantly reduced CFA-induced hind paw edema. The effect was partially blocked in the ADX rats. EA significantly increased plasma levels of corticosterone but produced no noticeable signs of stress. Conclusion: At 10 Hz but not 100 Hz, EA suppresses inflammation by activating the hypothalamus-pituitary-adrenal axis (HPA) and the nervous system.